Aegon The Conqueror

Aegon I Targaryen, also known as the Conqueror, was the first Targaryen king of Westeros. He led his people to the island of Dragonstone to escape the Doom of Valyria. Being the last of the Valyrians, he also had the last of the dragons at his command: Balerion, Vhagar, and Meraxes. Aegon rode the largest of the three, Balerion the Black Dread. Vhagar and Meraxes were ridden by his sister-wives Rhaenys and Visenya. To the east of Dragonstone was the remnant of the now defunct Valyrian empire and to the west was the Seven Kingdoms of the Andals. Instead of reestablishing Valyrian rule in Essos, Aegon chose to sail to Westeros in order to forge a new kingdom out of fire and blood.

Aegon and his forces landed on the western coast of the continent in the area now known as King's Landing. One by one Aegon began to conquer the Seven Kingdoms. The first to fall was the Kingdom of Harren the Black consisting of the Iron Islands and the Riverlands. Aegon and his dragons laid waste to Harren's "impregnable" fortress of Harrenhal. Afterwards he split the Iron Islands and Riverlands into separate areas giving lordship of the areas to the Greyjoys and Tullys respectively. The Stormlands were defeated when Aegon's bastard half-brother, Orys Baratheon, slew Argilac the Storm King. Aegon rewarded his brother with the seat, lands, and sigil of the Storm Kings thus creating House Baratheon. Unbeknownst to Aegon, House Baratheon would later come to be the greatest threat to House Targaryen since the Blackfyre Rebellion.

The Kingdoms of the Reach and Westerlands were conquered in a single day. King Mern Gardener of the Reach and King Lorren Lannister of the Rock united to battle Aegon in the fields of the Reach. This battle was known as the Field of Fire and is the only time Aegon unleashed all three of his dragons at the same time. The armies of Reach and Rock were decimated and King Mern along with his sons was slain. Seeing this destruction, Lorren Lannister bent the knee and was allowed to continue as lord of Casterly Rock and the Westerlands. After this battle Aegon was annointed as King of Westeros by the High Septon in Oldtown.

In an effort to maintain Northern sovereignty, King Torrhen Stark marched south against Aegon's forces only to bend the knee at the sight of dragons. House Stark was allowed to continue as Wardens of the North. The Arryn's of the Vale also knelt to Aegon, though the details are unknown. Of all seven kingdoms only Dorne was able to withstand the onslaught of Aegon's forces by engaging in guerilla warfare. Aegon chose to leave Dorne to the rule of the Martells as a sovereign nation. Dorne would later come under Targaryen rule through a marriage pact. Having conquered six of the seven kingdoms, Aegon I ruled Westeros until his death in 37 AL.